engine won't run well after changing oil/filter

[gathem]

I changed the air filter, oil filter, the oil, and impeller yesterday. The engine no longer starts.

Not sure about the old oil filter but all the new parts came from volva dealer.

Its an MD30a.

I've done some googling and I'm not sure if the suggestions are applicable.

I was pretty careful not to under/over fill the oi but its not super clear from looking at the dip stick. I used the oil the dealer provided 15W-40.

Any help would be appreciated!

[Cheechako]

If the engine ran prior to an oil change, I would be looking for maybe shut off solenoid issues or electrical connectors. Does it turn over but not start? More info... I cant think of anything you can do with an oil change other than completely fill the crankcase that should keep it from running....

[gathem]

It cranks and even sort of starts. Its not running well (sounds off) and will quickly die. It ran fine yesterday.

[Cheechako]

You did nothing to the fuel system? Didn't open the filter(s) just to look?

[irwin37]

did you by chance also change the fuel filter?

[gathem]

Did not touch the fuel filters etc. I did pump the fuel pump manual lever (for bleeding the system) 3-4 times mostly out of curiosity (after the oil/filter change the plan was to do the fuel filters). I didn't let any air into the fuel lines though.

[jkishel]

You say you changed the air filter. I'd suggest you double check to make sure that the air intake did not somehow become constricted; new filter sucked into the intake manifold, new filter stuck sideways in intake, shop rag left in there, etc. If air intake is not a problem, the fuel system is likely your next suspect.

[Stu Jackson]

Originally Posted by gathem

Did not touch the fuel filters etc. I did pump the fuel pump manual lever (for bleeding the system) 3-4 times mostly out of curiosity (after the oil/filter change the plan was to do the fuel filters). I didn't let any air into the fuel lines though.

If it pumped at all, you have a leak somewhere. It should have been impossible to pump. Check the vent screw and tighten the filter body.

An old friend taught me an important lesson:

Do one thing at a time, so if it doesn't work, you'll know what to look for.

Stop fiddling with other stuff and stick with the task at hand.

It sounds like something's loose on your fuel system.

[gathem]

Its the fuel system...
Unscrewed the fuel pump but and pumped the priming level. Only air came out. Checked the primary filter and its dry. Poured some diesel in the primary filter, pumped the priming lever until fuel came through without bubbles. Started right up.... Then died 45s later. Checked the priming lever/but and there's no fuel..

Hmmm

[Kokanee]

Diesels are relatively simple. They just need air, fuel and compression to run. The most common problem is lack of fuel.
Whether it's just coincidence, or you accidentally pulled or knocked a fuel line; there a very good chance its air in your fuel system. I'd suggest changing your fuel filters and bleeding your fuel system.

Read your manual if you haven't done it before. It's probably the most required mechanical skill needed for boating.

[jkishel]

Is there fuel in the tank? If so you need to check the system from the tank to the primary filter component by component. There may be a small clogged screen on the fuel pickup inside the tank. Are all fuel shut offs open? Check for air leaks at all fittings up to the primary filter housing. Change primary fuel filter and gaskets then bleed the system.

[Mycroft]

Something's def wonky. How would changing the oil filters cause the primary fuel filter to empty?

[Schrewsburyduo]

Where are you located? Did you run engine prior to changing oil?


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[hellosailor]

Priming pump is a rubber diaphragm pump maybe? Which may have been waiting for a chance to fail with a hole in the diaphragm? Which opened up when you just now used it?


That could explain everything. Might be possible to open up & eyeball to confirm.


FWIW I've had folks like Goodyear, Gates, Firestone, tell me that anything made of rubber (engine mount, belt, hose, etc.) should be replaced every five years if not sooner. They just deteriorate from air and chemicals and aren't intended to last longer than that.

[gathem]

Thanks for all the help.
It's 100% an air in the fuel system problem. The odd thing is I can't seem to prime the fuel system properly.

I unscrew the lid of the primary filter (empty). Fill it with clean diesel. I unscrew the priming nut, and pump the priming lever until airless diesel comes out. I screw the nut in. I go back to the primary fuel filter (no longer full) top it off with diesel. Go start the engine. It runs great for about 45 seconds then dies. If I unscrew the priming nut and pump the priming lever only air comes out. If I check the primary fuel filter its empty. The boat has plenty of clean diesel in the tanks. The fuel valve is open.

Not sure what else to do. My plan is:

Buy primary fuel filter replacement.
Buy a filter wrench small enough to unscrew my secondary filter (couldn't unscrew by hand).
Prime the two new filters, prime the fuel pump, maybe prime the injectors.

If that doesn't work I'll bring in a mechanic and hopefully learn something.